And I'm Audie Cornish. Deadly tornadoes swept through the Midwest overnight and this morning, killing at least eight people. The storm system hammered parts of Nebraska, Kansas, Missouri, Illinois and Kentucky, where it still poses a threat.

As NPR's David Schaper reports, hardest hit is the small city of Harrisburg in southern Illinois.

DAVID SCHAPER, BYLINE: Many of the people of Harrisburg went to bed last night knowing there was a threat of severe weather, but what they woke up to in the darkness at about 4:30 this morning few could imagine.

Harrisburg Mayor Eric Gregg describes the frightening scene.

MAYOR ERIC GREGG: When the sirens were going off this morning, I walked out of my home with my family and I looked and it was eerily quiet. And the sirens were blaring. And I had a heart – just a gut feeling that something dreadfully was wrong.

SCHAPER: The National Weather Service says it was an EF-4 tornado that hit Harrisburg. That's the second highest rating it gives to twisters. A forecaster estimates top wind speeds of at least 170 miles an hour. The twister cut a wide path of destruction through this city of about 9,000 in southern Illinois. An entire strip mall was leveled and reduced to a pile of debris. At least 200 to 300 homes were destroyed or damaged. Even the Harrisburg Hospital was not spared, as video shows a wall stripped away and hospital rooms and beds exposed to the elements.

Mayor Eric Gregg says in addition to those killed, the injured in Harrisburg close to 100.

GREGG: This morning, the city of Harrisburg had a horrific event. The loss of our lives breaks my heart today.

SCHAPER: The mayor says search rescue and recovery efforts will continue in Harrisburg until everyone is accounted for, though there are no reports of anyone still missing. And the city is imposing a curfew in the damaged areas at six o'clock tonight until 6:00 tomorrow morning.

Harrisburg isn't the only city dealing with the aftermath of devastating tornadoes. This rare, late February but spring-like storm raced across the center of the country overnight. At least two people died in Missouri and the popular resort town of Branson suffered severe damage to hotels, concert halls, homes and businesses.

After touring the damage, Missouri Governor Jay Nixon told reporters he believes many people may have been spared because after the devastating tornado that hit Joplin, Missouri, last year, they'd paid particular attention to this storm's warnings.

GOVERNOR JAY NIXON: I think people understand that the early warning systems we have in place now are serious. We've seen lives saved across our state, whether it's Joplin or other areas around the country. I think people understand that when those sirens go off, when people say, go to the basement, that the best thing to do is to follow those plans and do it.

MIKE HUDSON: Tornado outbreaks this time of the year are rare, but they're not unprecedented.

SCHAPER: Mike Hudson is chief operations officer for the central region of the country for the National Weather Service.

HUDSON: This storm system is actually part of a very large winter storm system affecting parts of the Dakotas. While areas around Kentucky, Missouri, Kansas, Illinois and Indiana are dealing with tornadoes, up across the Great Lakes and through the Dakotas, they're dealing with near blizzard conditions and upwards of a foot of snow.

SCHAPER: And Hudson says this dangerous storm system continues moving east with watches and warnings still in effect for parts of eastern Kentucky, Tennessee, Ohio, West Virginia and parts of the Carolinas.

David Schaper, NPR News. Transcript provided by NPR, Copyright National Public Radio.